Previous docking systems include pier and seawall type docks that require substantial expertise on the part of the helmsman to come alongside in varying current and wind conditions and also normally require tying up dock lines and the like. Usually a gangplank must then be put into place to allow transfer of passengers and cargo between the boat and the dock. There have been some attempts to improve upon this by incorporating a gangplank into the dock design that lowers onto the boat deck after the boat is secure in its moorings. There have also been efforts to incorporate the gangplank into the boat design for lowering onto the dock or shoreline as was done with old riverboat steamers. In any event, skilled helmsmen, dock lines and deckhands, and special gangplanks are normally required.
Prior art docking systems are constrained by conventional boat design which lacked the capability to control raising or lowering of the boat adjacent to the dock. The preferred embodiment of the present invention was made possible by the advent of air lift boat designs, including the Air Ride Boat Hull inventions of Applicant, the Surface Effect Ship (SES), and Hovercraft which raise significantly when their underside air chamber is pressurized with air supplied by an on-board blower.
Following are some prior art references that attempt to resolve at least some of the deficiencies described above. The first of these is a high speed boat docking scheme shown by Greer, U.S. Pat. No. 3,820,490 who teaches a hydrofoil type craft that approaches a fixed position long elevated track at high speed. The high speed is necessary to keep the boat elevated above the tracks. There is an elevated portion of the track where wheels located on the underside of extensions on either side of the craft make contact with the track. It is at that point that craft power is cut and docking can hopefully be accomplished. Undocking is accomplished by accelerating forward down the same track. Greer does not include any means to accomplish docking by simply raising and lower the hydrofoil craft while dockside since his craft cannot do that. Further, Greer's system is rather elaborate and would appear hazardous since precise close quarters navigation at high speeds is required.
Patents related docking schemes for air lift type craft include Ford, U.S. Pat. No. 3,990,258 and Hardy, U.S. Pat. No. 3,403,652. Ford utilizes ramps for launching a Surface Effect Ship (SES) to and from a beach. This ramp may include parallel tracks or a carriage. In either case, once initial contact is made with ramp, a winch is used to haul the boat onto the beach and there is little relationship to the instant invention except that Ford also utilizes an air lift type boat. Hardy shows a hovership docking concept where a fully skirted and hence amphibious hovercraft drives on to a deck of a larger displacement ship. The displacement ship is composed of catamaran hulls joined together by structure that forms a landing bay or deck for the hovercraft. The hovercraft drive up onto the landing bay which is fitted with a holding ramp at its back end to facilitate hovercraft entrance and exit since the landing bay is purposely above the waterline. The hovercraft rests completely above the water when secured. The latter feature is desireable since a major purpose of Hardy's invention is to provide a means to transport fully amphibious hovercraft long distances inside of more or less conventional catamaran like displacement hull forms. Hardy's invention requires a special displacement hull form with an above the waterline landing bay, a fully amphibious hovercraft, and does not have attachment arms for loading or unloading cargo or passengers.
The are also patents that show a ball and socket system. These include York, U.S. Pat. No. 3,473,483, a substantially hemisphere shaped track system; Goddard, U.S. Pat. No. 2,511,979; and even a foldable windged hydrofoil watercraft, Hanford, U.S. Pat. No. 3,139,059. York's ball and socket system, a downwardly sloped track consisting of a curved surface of balls captured in sockets that support a sliding mat in an amusement park ride, is hardly related to the present invention's docking socket attachment system.
Goddard's invention includes gas bearing supported tracks used to support a high speed vacuum tube transportation system. Goddard's gas bearing supported track system reduces friction to an absolute minimum but the track portions must remain in close but non-contacting proximity at all times during high speed operation. Further, Goddard cannot separate his track system by pressurizing an air chamber in the underside of his vehicle since he lacks such structure and a water surface to retain air pressure. Hanford presents a winged hydrofoil watercraft wherein the wings can be folded up and down to gain the maximum benefit from aerodynamic lift, especially in ground effect. Since Handford's wings are not used for docking or attachment there is little relationships to the present invention's movable docking attachment arms.
In its preferred embodiment, the present invention utilizes attachment arms that settle onto the dock as blower power is reduced on air lift vessels. This also secures the boat at the dock, eliminating handling of dock lines. In most applications, the attachment arms also serve as gangplanks. This presents a very low cost and practical approach to a problem which boat owners have come to accept as lacking a solution, because they have learned to live with the prior art cumbersome, time consuming, and hazardous methods of docking.
While the aforementioned air lift boat designs have rigid sidehulls or other rigid structure which normally extend the length of the boat and are water contacting at all times, restricting these vessels to marine service, it should be mentioned that there is another air supported craft to which the present technology can be applied. The pure Ground Effect Machine (GEM) has flexible skirts or seals around its full periphery that actually clear the surface over which it moves, thus making the same truly amphibious. The docking systems used for GEM's are more like those used for seaplanes, since they utilize ramps that slope into the water. The GEM goes up the ramp and then reduces blower power to settle onto a flat landing area. The docking system of the present invention is adaptable for use with GEM's where landing ramps are not available.
The present invention can also be applied in an alternative embodiment to other more conventional marine vessels which lack an air lift system. A U-shaped floating dock and a movable attachment arm in combination with a mating socket track provide advantages for all vessels.